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High speed data collection

One of the most amazing energy data collection projects in Europe has recently been implemented in the Netherlands by Essent Metering Services. Before pushing the ‘on’ button for the TMS system, however, the Essent and GÖRLITZ engineers had to cope with some overtime, but in the end the deadlines were successfully met.

The Dutch AMR metering business has only dealt with C&I
customers up to now – as is common with most European
energy markets. Prior to the installation of the new system at Essent, most of the Dutch utilities had MV-90 or Siemens C-2000 data collection systems in use. The Essent project is the first project for GÖRLITZ in the Netherlands, and the challenge for GÖRLITZ was to replace a couple of single solutions which were no longer adequate to meet the requirements of the deregulated market.

The Dutch Electricity Grid

Essent collects load profile data from approximately 60,000 metering data points on a 5-minute interval basis. The data is processed according to several validation criteria during the night, so that a full picture of the C&I customers’ energy demand is available at 08.00 the following morning. The fact that the measurement interval resolution in the Netherlands is 5 minutes, instead of 15 minutes, as in Germany and Italy, or 30 minutes in the UK, means that the mass of data and the system workload is correspondingly higher too. The overall system performance required is comparable to a daily data collection of 153,000 load profile channels based on 15 minute reads.

The TMS system is operated by Essent Meetbedrijf, the Metering Services Company of Essent Energie B.V., the Netherlands – a major player in the energy market, which is deregulated. Customers can decide on their choice of meter operator, as well as energy supplier.

Deregulated meter operation

The chosen operator is responsible for the whole process flow of metering, including meter installation, operation, maintenance, and reading. The operator is also responsible for the compliance of the meter with metrological requirements and for compliance of data communication with traders in the open market.

90% of the customers serviced by Essent Meetbedrijf belong to the grid network of the Essent group itself, and the other 10% of the data is read by third-party grid operators. Essent operates the TMS system throughout the Netherlands. The 60,000 measurement points are distributed in 12,000 modem sites in the Netherlands, where a couple of meter points are used in a multi-point reading mode. The system covers all segments of energy measurement; the gas segment in particular will undergo a large expansion in the next few months. The readings for this segment require specific handling and reports that are able to treat the ‘gas-day’ which has a billing cycle ‘from 6 to 6’ round the clock. The measurement intervals in gas and heat are on an hourly basis, which leads to 24 values a day, while electricity data has up to 288 values a day.

Slow meters, high-speed system

The first site installations were implemented in the early 1980s, working with 300 baud half-duplex communication. However, the major installations in the metering field took place in the late 1990s, offering 2,400 or 9,600 baud. The new TMS system is based on a fully implemented ENZ2000 data collection using 128 modems in parallel and the Energy Data Warehouse® for validation. The meter technology in the field comes from various manufacturers such as Landis+Gyr, Datawatt and Kamstrup. Beyond this the system supports a wide range of different protocols to read all popular meters, including the new protocol standard DLMS.

The TMS system consists of three main components. The ENZ2000 client server data collection system is used as the front-end for automatic meter reading. Each of the 128 modems has to make about 90 calls in a row so that all 10,000 meters are read. About 60% of the meters are read via the PSTN network and the remaining 40% are based on wireless GSM communication.

The data collected is then stored directly in the Oracle® Database of the Energy Data Warehouse. The EDW system performs several validation steps and examines the plausibility of the load profile data to identify missing or invalid values. During the validation process, the individual load profile per day is accumulated and compared with the total energy register of the meter. In addition, the EDW is the daily working tool of Essent’s system operators, through which they control the data flows and correct value chains.

The third system level is Essent´s ‘PI’ System, the central EDM system. The Energy Data Warehouse forwards only validated results, or substituted values in the case of missing data, to the PI system – the ‘metering database’. Every single value has an individual mark which declares it ‘provisional’ or ‘final’. Only those values that have passed all the applicable validation steps become ‘final’ values. Values that have failed one or more checks are ‘provisional’ so the system can detect that a corrected value will follow later on. Finally the PI system aggregates all the data and sends it to the billing department and the energy suppliers, to enable them to charge their customers.

The system operates with an impressively high quality for the data output: 99,5% of the collected metering data is complete and checked for plausibility and forwarded to the final recipients. According to the market rules Essent Meetbedrijf can correct and deliver completed data for the previous ten days, after which the data must be frozen. In the case of reading failures most of the errors can be detected and corrected quickly, or the data is automatically re-read at a second attempt, so that TMS is able to deliver the highest possible amount of proven data within a single day.